Method of packing wells



Feb. 9, 1943. c. J. coal-:RLY

METHOD OF PACKING WELLS originalv Filed Jap. 24; 1938 Y a 6 .7 C M SM MM 0 y HA RR/J, 'ff/5CH, F o.: TER a HARR/J Y' atented Feb. 9, 19432,310,397 Mirrnop oF PACKING WELLS Clarence J. Coberly,

Los Angeles, Calif., assignor to Kobe, Inc. Huntington Park, Calif., acorporation of California originall application January 24, 193s,sei-iai No.

186,597. Divided and this application February 10, 1940, Serial No.318,300

i claims.' (ci. liss-26) This appiicatidh isa division of myapplicationV Serial No. 186,597, led January 24, 1938, for "Gravelpacking for wells, now Patent No. 2,217,- 215, granted Oct. 8, 1940.

This invention generally relates to the well art and more particularlyto a method of packing a well so as to prevent sand from the wellformation from entering the bore of the well. Although the invention hasa wide range of uses, it has particular utility in the oil well pumpingart, and, accordingly, the preferred embodiment will be described inconnection therewith for the purpose of illustration.

In many oil iields, the oil producing zone is l comprised in part atleast of relatively flne sand,

which, during normal pumping of a well therein, tends to beme detachedfrom the formation and to pass through the pump and associatedproduction equipment, causing excessive wear and requiring frequentshut-downs for equipment repairs and replacements. -Thus, pumps, tubing,

- pack the well formation ,with gravel, sometimes regas traps, and otherproduction equipment which are operated under such conditions have -anextremely short life, and the annual cost of replacement and repairs forsuch equipment due to such production of sand in the oil is asubstantial burden on the oil industry. Another major diilicultyencountered under such pumping' conditionsV is the tendency for thepumping equipment and tubing to become filled with sand, or sandedup, sothat the equipment. cannot be operated. This always requires a thoroughcleaning of the tubing and pumping equipment, which usually necessitatesremoval of the pump and an extended lbailing of the tubing, both ofwhich interrupt the production from the well, causing great economicwaste and loss to the operators. Therefore, it is a primary object ofthis invention to provide a method of treating a well so asto' preventthe above-stated difficulties now commonly experienced in the art.

For the purpose of this speciflcation, the term ""sand is defined asmeaning any undesirable substance formed of discrete particles normally.

found in a well and which it may be desired to of the well,l such as.for example, truef sand, shale, mica, or other similar substances.

ness of the sand, producing conditie .low bottom-hole pressures, orother factors, been possible. to set a liner which will properly controland prevent the production of. sand. The usual dlmculty is that Wheremerely a ilne perforation liner is. used, the formation sand packstherearound to form a bed of sand of low permeability, with an attendantpressure drop therethrough, greatly decreasing the maximum productionfrom thel Well. I n addition, a liner having a ne mesh perforation willreadily clog to further reduce the production. It is, therefore, anotherobject of my invention to provide a method for so treating a well that aliner having perforations of relatively large mesh may be employed.

Attempts have been the space between made in the prior art to theperforated liner and ferred to as gravel-packing, for the purpose offorming a bedof gravel therebetween substantially impervious to the nowof'sand therethrough but permitting oil to flow into the pump throughthe liner. Such attempts at gravel-packing have not vproved satisfactorybecause ofthe lack of knowledge of the factors involved and a propermethod of application thereof and .apparatus therefor. Accordingly, itis another. object of this invention to provide a method for packing a'well .with a substance comprised of discrete particles, such as, forexample, gravel, in which the previously indeterminate factors are givenanovel solution. I

Although gravel is al cheap-and satisfactory substance for use in myinvention, it will be understood that any suitable substance comprisedof discrete particles may be substituted therefor without departing fromthe spirit ofV my invention. f

. By testing ou wens in the onahoma city Field,

near-Oklahoma City, Oklahoma, in which considerable trouble has beenexperienced as a result of sand in the pumped oil, I have established aexclude from entering the production equipment 'In the prior art,attempts have been made to z overcome the .above-stated diiliculties bysetting a perforated liner at the bottom ofthe well, having perforationsof the'prop'er mesh to prevent the entry of the formation sandtherethrough. These attempts have not been successful, however, becausein many oil fields, due to the finetion,

number of relevant facts. For example, in some wells in this iield theproducing-zone is almost continuous sand from top to bottom, the 'sandoccurring in layers of varying hardness, due to different binders,'different amounts of binder, different degrees of compaotlon'of the wellformaand other conditions. Furthermore, in most of the' older wells ofthis ileld, large cavities have formed in the well formation throughoutvthe length of the 4.producing zone as a result'of the formation sandbecoming detached and being produced with the oil during the flowing andgas it has vnot -has formed around the well,

` bridges between the gravel grains.

left stages of production of the wells. Many of the Wells in this fieldare now being pumped, or are soon to be placed on the pump, but sanddiiilculties continue during the pumping, the magnitude of which dependon the age of the Well, its present production, length of period ofnatural iiow, length of period of gas lift, gas-oil ratio, Welllocation, and any other factors which have affected or may still affectthe size of the cavities between the well and the producing zoneformation and the ability of the oil to carry sand from the presentproducing zone to the bore of the well. In some of the newer wells ofthis eld which are being pumped but in which only a small cavity it hasbeen found that if such a-well is shut down for as short a period as aquarter of a minute, the pump becomes sanded-in due to settling of thelarge percentage of sand carried by the oil in the production tubing.Some or all of these conditions may be found in other oil fields.

In packing gravel around a well base, there are three principal problemspresented: (l) selection of the proper mesh gravel to prevent travel ofsubstantial quantities of formation sand therethrough with the oil to bepumped; (2) proper placement of the gravel; and (3) the selection of 'aliner having perforations of a proper mesh to prevent the gravel frompassing therethrough. The latter problem is readily disposed of afterselection of gravel of the proper size, as a liner perforation of twicethe grain size at the ten percentile may be employed if an assortedsize.

gravel is used, or a perforation twice the width of the grain size ofthe individual grains may be employed if a closely graded grave1 isused.

'Ihe selection of the proper size or mesh gravel" to screen theformation sand is more diiiicult. Using sand grains taken from a typicaloil well having bad sand conditions and passing them through a bed ofgravel, I have discovered that 1 stable bridging of the sand grains overthe spaces between the .gravel grains occurs when the diameter of animaginary circle inscribed in the space between the gravel grains is notover two times the diameter of the ten percentile sand grain size. Thegravel size may also be stated as: the diameter of the largest gravelgrains in a singie classified gravel (Tyler scale) suitable for gravelpacking is approximately thirteen times the effective sand grain size atthe ten percentile. The se conclusions are stated for gravel grains oithe maximum size that can be used to forme.: stable sand bridgetherebetween, although gravel grains of one or possibly two screen sizes(Tyler scale) smaller would provide an additional factor of safety ininsuring the formation of stable sand Accordingly, it is a furtherobject of my invention to provide a substance comprised of discreteparticles, such as, for example, a gravel, for packing an oil well whichbears the above-stated size relation to the size of the formation sandtherein.'

Regarding the placement of the gravel in an oil well, I have found thatthe gravel should be transported to the point of placement in such amanner that the possibility of clogging of the gravel during placementis reduced to a minimum. Furthermore, the angle of repose of the gravelmust be small so that the gravel may fill all crevices and pockets inthe well formation as fully as possible. Also, the method of placingthegravel should be such that if any interruption occurs, placing of thegravel may be resumed without serious difliculty. Further, any material'mixed with the gravel to facilitate placement thereof should be readilyremovable by washing, natural ow of the oil, or otherwise, andpreferably should be soluble in or miscible with the produced oil. Also,provision should be made for the placing of additional gravel in thewell at some later time in case of settling of the original gravel bedor incomplete lling of the formation cavities. Furthermore, the gravelshould preferably be placed from below; that is, the iiow of the gravelshould be from the bottom of the hole upward, in order to reduce to aminimum the caving of the formation Walls during'placement of the graveland to reduce the possibility of a portion of the well hole remainingfilled with original formation sand. Therefore, it is another object ofthis invention to provide a method and composition of matter capable ofaccomplishing the foregoing desired conditions.

'Ihe conditions set forth in the preceding paragraph are best fulfilledby mixing the discrete particles, such as gravel, with a viscous fluidand placing it in a state of pressure-mobile mixture in the well cavity,and, accordingly, this is still another object of the invention. Thismixture, being pressure-mobile, will also have the advantage that it maybe handled as a iiuid, i. e., pumped through tubing in much the samemanner that mud is pumped.

Another object of the invention is to'provide a novel composition ofmatter comprised of a substance made up of discrete particles having thesize characteristics stated hereinabove, for use in packing a well.

Likewise, it is an object of the invention to provide a pressure-mobilemixture of a substance formed of discrete particles and a viscous fluid.

I provide an apparatus for pumping a well comprising a tubing in thewell having a perforated liner at the lower end thereof, and a checkvalve connected to the bottom of the liner permitting a material to beexpelled from the tubing into the well but preventing the material frompassing from the well through the valve and into the liner.

I provide an apparatus for use in a well, comprising a tubing in theWell, having a plurality of valves spaced along the length of suchtubing, and means for selectively passing a substance out of the tubingand into the well through any one of the valves as desired.

Another object of the invention is to provide a method for packing awell in which discrete particles are pumped into the Well from the lowerend of a tubing, the pumping pressure values being utilized to indicatecompletion of the packing operation.

Although the principal object of the invenmay' be advantageously appliedto wells having little or no sand diiiiculties. In many wells, a1-though little sand diiiiculty is experienced, considerable trouble ishad with soft portions of the formation, such as clay, for example,caving or heaving to shift the bore of the well or to pinch off theliner or other tubing therein. This is due to the fact that there isalways a substantial space in a well-around the production tubing. Bypacking this space as describedherein, these diiculties may be, in partat least, obviated. and, iaccordingly, this is another object of theinvenion.

Other objects and advantages of my invention will be evident from thefollowing specication, which is for the purpose of illustration only,the claims, and the drawing in which:

Fig. 1 is a diagrammatic sectional view of a well having my preferredform of apparatus therein.

Fig. 2 is an enlarged sectional view of the lower end of the apparatusof my invention.

Secured in the lower end of the water tubing II,V

as by a` suitable combination packer and hanger I2, is a permanently setouter tubing I3 at the lower end of which is secured by a suitablecoupling a liner I4 having perforations I5 in the walls thereof. It willbe recognized, however, that the outer tubing I3 and liner I4 may beformed integrally in one piece, by merely perforating the lower end ofthe outer tubing; As shown in detail in- Fig. 2, a valve shoe I6 isthreadedto the lower end of the liner I4 and is provided with-aninternally threaded central bore I1 and a seat I8 therearound. Thecentral bore I1 communicates with a vertical passage I9 having acounterbore 20 internally threaded \to receive a threaded plug 2l.Radial passages 22 communicate between the counterbore20 and theexterior of the valve shoe I6. A ball valve member 23 is held inupwardly seating engagement with the 4vertical passage I9 by means of acompression spring 24 bearing against the threaded plug 2|. The valveshoe I6 and the mechanism therein thus provide a valve means adapted topermit materials to pass outwardly through the vertical passage I9 andthe radial passages 22, forcing the ball valve member 23 downwardlyagainst the action of the compression spring 24, but prevent materialsfrom passing inwardly from the well through the radial passages and thevertical passage into the central bore. Threadedly received in the.central bore I1 is the lower end of a wash tube 25, which may beextended through the water tubing II, the outer tubing I3, and the linerI4 into uid-tight seating relation on the seat I8.

As shown in Fig. 1, the lower end of the wall I may have one or morerelatively large cavities 30 extending back from the well bore into the1miducing formation of the well. As pointed ou hereinabove, lthesecavitiesv 3II are normally formed during the natural flow, gas lift, orpumping stages of yproduction from the well, and are caused byvrelatively soft portions of the well' formation, including considerablequantities of iine sand, becoming detached therefrom by the flow of oilinwardly froin the .formation to the bore of the well. l The depthand'cross-,sectional area of th'e cavities 30 depend largely` upon thehistory of the well and the flow and pumping conditions therein, and mayvary from a foot or. two in length to many feet in length. A sindicated, it is the primary purpose ofthe present invention to flll thecavities 30 andthe space between the liner I4 and the well formationwith va bodyof discrete particles, such as gravel, so as to form ascreen preventing the passage of substantial quantities of formationsand `therethrough' and through the perforations I5 into the liner andouter tubing I3.

Adapted to be connected to the upper end of the water tube 25 by meansof a coupling 32 is a supply pipe 33 having a suitable pumping mecha-Vnism 34 in the line thereof, the pipe 33 being connected to a closedsupply tank 35 which'acts as a r'eservoir for the material to be usedfor packing the Well.

In operation, and prior to the setting of the outer tubing I3 in thelower end of the water tubing II, the lower end ofth'e well I0 iscleaned by hailing, or otherwise, so as to remove substantially all ofthe sand and other foreign materials which may have accumulated in thebottom of the well during prior operations in producing from the well.Such hailing or cleaning is a common expedient` in the art and will befamiliar to those versed in the industry. When the bot-- -tom of thewell I0 has been thoroughly cleaned of sand -and other foreignmaterials, the outer tubing I3, with the packer and hanger I2, the linerI4, and the valve shoe I6 attached thereto, is run inthe welltosubstantially the position shown in Fig. 1 by any means well known inthe art, such as a string of tubing connected to the upper end of theouter tubing (not shown), and the packer and hanger is then utilized tohold the outer tubing in place at the bottom of the well.'

As ,will be noted, the packer I2 forms a seal between the outer tubingI3 and the Water tubing I I, which is utilized for a purpose to bedescribedl hereinafter. Although I have sh'own a well III in whichthewater tubing II has been inserted in accordance with the usual wellpractice, it will be recognized that in some wells no water tubing isprovided at the lbottom of the well and that the packer and hangerv I2may be positioned in direct engagement with th'e walls of the wellwithout departing from the present invention.' When the outer tubing I3is set in position in the well I0, as`

described, the wash tube 25 is then run intothe well through the watertubing II and the outer tubing I3 until the lower end thereof seats onthe seat I8 of the valve shoe I6, at which time thev outer tubing I3into the position shown in Fig. 1,

in which case the wash tube is threaded into the valve shoe prior toinsertion in the welll and only one operation is required thereby'.v A

When the outer tubing I3 and the wash tube 25 are in position, as shownin Fig. l', the supply pipe 33 is connected to the wash tube by means of.a coupling such as 32, so as to connect the wash tube with the supplytank 35'through the pump` ing mechanism 34. The supply tank 35 is thenfilled with the substance with which it is desired to pack the well IU,and, as described hereinabove,

for this purpose I prefer to use a pressure-mobile mixture of discreteparticles, such as gravel, and

a viscous fluid, such as a hydrocarbon derivative obtained from the sametype of oil as is to be produced from the well. This mixture is mixed inthe supply tank 35 and is then pumped there-A from by the pumpingmechanism 34 through the pressure-mobile mixture flows upwardly in thewell I0, fllling the cavities 30 and the space between the formation andthe liner I4 until it reaches the packer and hanger I 2, at which timethe pumping pressure on the pumping mechanism 34 rises to indicate thatthe bed 3| has been completely formed. When this material rise inpressure occurs, the operation of the pumping mechanism 34 is stopped,the supply pipe 33 and coupling 32 are disconnected from the wash tube25, and the wash tube is then unscrewed from the valve shoe I6 andremoved from the well. 'I'he interior of the liner I4 and outer tubingI3 is then hailed to remove any gravel from the wash tube therein, anysuitable type of pumping mechanism may then be lowered through'the wellI0 into pumping position with relation to the liner I4, and pumping ofthe well may then be cornmenced. During pumping, oil or other well uidflows from the formation through' the bed 3| comprised of discreteparticles, such as gravel, cws through the perforations I5 of the linerI4 and may then be pumped to the surface of the ground. Due to properselection of the size of the discrete particles with reference to thesize of the formation sand, and the proper selection of the size ofperforations I5, the discrete particles are substantially prevented fromentering the liner I4 through the perforations I5 thereof, and theformation sandl is prevented from passing through the bed 3| of discreteparticles. By the selection of discrete particles of the proper sizerelative to the size of the formation sand, as pointed out herein, asubstantial quantity of the sand is effectively screened from entry intothe liner I4 without decreasing the normal ow of oil or other well fluidthrough the bed 3|. By using a. viscous fluid for the pressure-mobilemixture, the mixture may be pumped as a fluid through the tubing andvalve shoe I6 and will readily flow into the desired position in thewell. By using a viscous fluid which is miscible or soluble in the oilor other fluid to be produced from the well, the viscous uid will bequickly washed out of the bed 3| by the well uid passing therethroughupon commencement of the normal pumping operation.

Although the invention has been primarily described in connection witha. well in which a pump is to be installed, it will be appreciated thatI do not intend to have the invention limited to packing a well to bepumped, since the invention is equally applicable to a well that is inthe natural flow or gas lift stages.

It will also be understood that when the packing operation is commenced,there is ordinarily a considerable head of oil accumulated in the bottomof the well IIJ, and particularly below the packer and hanger I2, andthat as the pressure-mobile mixturer is passed upwardly in the wellaround the liner I4 this head of oil must be displaced. To prevent theoil from being forced back into the well formation, the perforations I 5are preferably continued up the liner I4 to a point adjacent the packerand hanger I2, so that as the pressure-mobile mixture is introduced intothe bottom of the well I 0 and upwardly therein, `the oil thereabove mayow into the liner through the perforations I5, thus preventing a highback-pressure from being built up on the producing zone formation.

It is sometimes desirable, however, to provide a special solvent forremoving the viscous uid from the bed 3| prior to commencement of thepumping operation. In such cases, I prefer to empty the closed tank 35of its pressure-mobile mixture, replacing it with a viscous fluidsolvent or other substance which will effectively cut the viscosity ofthe viscous fluid, such as distillate in the case where a viscoushydrocarbon is employed as the carrying agent for the discreteparticles, which is then pumped through the supply pipe 33 and the washtube 25 and into the well as described, from which it flows through thebed 3| so as to decrease the viscosity of the viscous fluid therein.This may be regarded as a modied form of my process, and can also beperformed by means of a standard perforation washer, as is well known inthe art.

Also, in some installations, I have found it desirable to precede thepacking operation by pumping a quantity of the viscous fluid to be usedinto the bottom of the well without any discrete particles therein, soas to form a layer of heavy fiuid at the bottom of the well, the purposeof which is to protect the viscous fluid in the pressure-mobile mixturefrom contamination by mixture with the oil or other well fluid from theformation. This operation will normally be carried out prior to pumpingof the pressure-mobile mixture into the well as described.

In Fig. 3 I show a modified form of apparatus which may be used inconnection with the apparatus shown in Fig. 1 to carry out a modiedmethod of packing a well. Similar parts are given similar indicatingnumerals with the suiilx a added thereto. The device shown in Fig. 3,and the method employed therewith, are frequently preferable where theproducing zone of the well is extremely long and where a long liner 4ais required, or where there are alternate blank and perforated zones inthe liner. In such cases, the liner |4a is divided into a plurality ofsections joined together by couplings 36, each of the couplings havinginwardly closing valves 31 therein comprised of openings 38 in the wallof the coupling provided with seats 39 adapted to receive an `inwardlyfaced valve member 40 resiliently held in engagement with the seat 39 bya spring arm 4| suitably secured to the coupling as by rivets 42.Although only one coupling 36 is shown in Fig. 3, it will be understoodthat as many of such couplings as desired may be utilized. The valves 31thus permit the pressuremobile mixture to be forced out of the linerinto the well |0a at various points along the length ,of the liner. Inthis form of the invention the Wash tube 25a is provided with a fitting45 adapted to be secured to the lower end thereof having basket packers46 at opposite ends thereof and radial openings 41 therein. In'operationof the device shown in Fig. 3, the liner I4a is iirst set in the well asdescribed with relation to Fig. 1, and the wash tube 25a is run into thetubing as described with relation to Fig. 1, and the pressure-mobilemixture is pumped therethrough and into the well as heretoforedescribed. Due to the long length of the liner I4a, the pressuremobilemixture cannot satisfactorily be pumped from the bottom of the inletshoe I6 above a certain distance above the inlet shoe due to the Weightof the pressure-mobile mixture and packing thereof in the cavities 30.When the bed of discrete particles 3| is thus formed to a certainheight, such as represented by the line C-C, pumping of thepressure-mobile mixture is discontinued, the wash tube 25a. is removedfrom the well, and the fitting 45 is attached to the bottom thereof as`shown in Fig. 3. The

top' thereof The f obtain wash tube 25a is then run into the well to apition in which the basket packers 46 straddle any one of the couplings36, preferably the lowest coupling through which it is possible to placethe mixture, and the pressure-'mobile mixture is then pumped downwardlythrough the wash tube 25a and outwardly through the opening 41, forcingthe valve member 40 outwardly against the resilient action'of the springarm 4I to permit the pressure-mobile mixture to be pumped outwardlythrough the liner I4a into the well above the bed 3| previously formed.Pumping is then continued as desired or until the pressure re` quiredtherefor rises substantially, and the pumping is then discontinued, thewash tube 25a is then moved until the basket packers 46 straddle anothercoupling v36, preferably the nextv higher in the liner Ma through whichthe mix ture can be placed, and pumping may then be resumed to forceVvthe pressure-mobile mixture. outwardly into the well through theinwardly closing valve 31 above that iirst used. This may be continuedas desired until the entire well is suitablypacked with a bed or beds 3lof discrete particles formed The wash tube a may then be withdrawn fromthe well, the well bailed, a well pump inby the pressure-mobilemixture.y

apparatus and method disclosed herein may be used without departing fromthe spirit of the invention, and, accordingly, I do not desire to belimited by the foregoing specication but intend to be granted the fullscope of the following claims.

I claim -as my invention:

l. A method of removing sand grains from the production ow of a well,including the steps of: forming a single classied body of discreteparticles in which thediameters of the largest particles areapproximately thirteen times the size Yof the sand grains in the well atthe' ten percentile; l disposing said body of discrete particles in thewell in the path of the production flow' therefrom; and passing saidproduction iiowthrough said body of discrete particles.

2. A method of removing sand grains from the production fiow of a well,including the steps of:

forming a single classiiied body of discrete particles in which thediameter of a circle inscribed in the spaces between thelargestparticles is approximately two times the size of the sand grainsserted, or production otherwise commenced as described in connectionwith Fig. 1. In the apparatus shown in Fig-3, the perforations 15ashould be selected of a mesh such that no discrete particles will beable to enter the perforations fromnthe inside of the liner I4;otherwise, when the basket packers 46 with the pressure- 'mobile mixturetherebetween are being moved through the liner, the perforations willbecome plugged. Liners with fine-meshed slots may be set withoutaiecting the wellproduction, due to the high permeability of the bed 3l,and thus it will be possible in most cases to select a liner` havingperforations which will n'ot plug with discrete particles when thepressure-mobile mixture is in engagement liner l4a.

After a well has been pumped or otherwise produced for some time with apacking bed 3| therein, the bed may settle, making it desirable to addan additional layer of discrete particles on the inwardly closing valves31 of the liner |4a may be utilized in such cases to increase the depthof the bed 3|, without disturbing the bottom portion ofthe bed, and thisis another modified use of the invention.

Although the invention has been described in I connection with a well inwhich cavities 3|) have already been formed during the past history ofthe well by prior flow conditions, it will be evident that extensivecavities around the perforated liner will increase thenatural productionof the well by increasing the formation area draining into the well,provided the formation sand can be held in place. It will therefore beevident that in new wells where no such cavities have been formed duringthe history of the Well,'it may be advantageous to create such cavitiesby any means well known in the art, such as underreaming the'well holeprior to the packing operation.

Although it is old in the art to underream a well to increase theproduction thereof, and although this does not play any part in thepresent invention, it will be recognized that underreaming inconjunction with the present invention may be distinctly advantageous innew wells so as to maximum production therefrom.

It will be understoodl that modifications of the with the inside of thein the well at the ten percentile; disposing said body of discreteparticles in the well in the path of the production flow therefrom;and-passing said production ow through said body of discrete particles.A

3. A method for packing a well having substantial quantities of sand inthe well formation of the producing zones thereof, including the stepsof: permanently setting a liner in a well opposite to a production zoneof the well; forming a bed of discrete particles around a portion ofsaid liner, said bed being substantially impervious to sand in the well;extending a tubing downwardly into said liner to a first positionadjacent the top of said bed; and passing additional discrete particlesdownwardly through said tubing and out through said liner at a pointabove said'bed so as to form an additional layer of said particlesaround said liner on the top of said bed.,V

4. A method-'for packing a well having substantial quantities 'of sandinthe well formation of the producing zones thereof, including the stepsof permanently setting va liner in a well opposite to a production zoneof the well; forming a bed of discrete particles around a portion ofsaid liner, said bed being substantially im pervious to sand in thewelk-extending altubing downwardly into said liner t'o a rst positionadjacent the top of said bed; passing additional discretefparticlesdownwardly through said tubing and outI through said liner at a pointabove said bed so as to,form an additional layer of said particlesaround said liner on the top of said bed;

raising said tubing upwardly to a second position in said well adjacentthe top of said additional layer without moving said liner; and passingadditional discrete particles downwardly through said tubing and outthrough said liner at a point above said additional layer so as to forma'further layer of said particles around said liner on top of saidadditional layer.

5. A method for packing a well'having a perforated liner permanently settherein, including the steps of:` forming a rst bed of discrete-parlticles around a portion of said liner, said bed being substantiallyimpervious tosand inthe I well; extending a tubing downwardly into saidliner Ato aposition above the top of said first bed;

and passing additional discrete particles down'-,

wardly through said tubing and out throughthe walls of said liner toform a second bed of said particles around said-liner'- abov'e said irstdownwardly through said liner and out through 10 the walls thereof at apoint above the top of said iirst bed to form a second bed oi saidparticles around said liner above said rst bed.

7. A method for packing a wellhaving a perforated liner permanently settherein, including 15 the steps of: setting a tubing in a tirst positionin the hner; passing a stream of discrete particles downwardly throughsaid tubing and outwardly through the walls of said liner to form aiirst bed of discrete particles around said liner, said iirst bed beingsubstantially impervious to sand in the well; raising said tubing to asecond position in said liner without moving said liner; and passingadditional discrete particles downwardly through said tubing andoutwardly through the walls of said liner to form a second bed ofdiscrete particles around said liner above said rst bed, said second bedbeing substantially impervious to sand in the well.

CLARENCE J. COBERLY.

